Environmental Geography

Transcription

1 Environmental Geography Lecture 9 Renewable Energy Lecture 8: Energy Generation and Use I. Biomass II. Hydroelectric Power III. Wind Power IV. Solar Energy V. The Transition 1

2 I. Lecture 9 I. Lecture 9 The commercialization of renewable energy involves the diffusion of three generations of technologies: First-generation technologies, which are already mature and economically competitive, include biomass, hydroelectricity, and geothermal power and heat. Second-generation technologies are market-ready and are being deployed at the present time; they include solar heating, photovoltaics and modern forms of bioenergy. Third-generation technologies require continued R&D efforts in order to make large contributions on a global scale and include advanced biomass gasification, biorefinery technologies, solar thermal power stations, hot-dry-rock geothermal power, and ocean energy. 2

3 I. Biomass Biomass is organic material, which has stored solar energy from sunlight in the form of chemical in the plants through the process called photosynthesis. Biomass fuels include Agricultural Wastes, Crop Residues, Wood, Woody Wastes & Organic Wastes etc. Unlike fossil fuels Biomass does not add carbon dioxide to the atmosphere as it absorbs the same amount of carbon while growing. I. Biomass 3

4 I. Biomass Advantages of biomass: Biomass is renewable Biomass is widely available Biomass is a cleaner fuel Biomass waste and byproducts can be used for fuel Disadvantages of biomass: Quantities of biomass for fuel are limited There is an issue of fuel crops versus food crops Removal of biomass may deplete soils Biomass yields low net energy II. Hydroelectric Power Conventional capacity nearly tripled in United States since About 10% of U.S. electricity comes from hydropower. 4

5 II. Hydroelectric Power Advantages of hydroelectric power: Provides electricity without air pollution Cheaper than fossil fuels Less hazardous than fossil fuels or nuclear energy Domestic source of energy Disadvantages of hydroelectric power: Dams cause lots of environmental damage downstream (changes in water regimes, water temperature, loss of wetland and riparian areas, impact to fish and other aquatic species, etc.) Costly to build reservoirs Short lifetimes on sediment laden rivers (ex. Matillija Dam) Hydropower Prospector III. Wind Energy Some facts about wind energy: Although wind currently produces just over 1% of worldwide electricity use, it accounts for approximately 19% of electricity production in Denmark, 9% in Spain and Portugal, 6% in Germany, and 1% in the US. Globally, wind power generation increased more than fivefold between 2000 and

6 III. Wind Energy Advantages of wind energy: Wind is a perpetual energy source Wind speed increases when demand is greatest Wind turbines can be installed quickly and take up little space Wind is a clean source of energy Disadvantages of wind energy: Intermittent power source and can only generate electricity when there is enough wind to spin the turbine Not aesthetically pleasing IV. Solar Energy Types of Solar Energy: 6

7 IV. Solar Energy Solar Thermal: Produces hightemperature heat by using lenses and reflectors to focus sunlight on water-filled tubes. The conversion of the water to heat energy is used to generate electricity. Solar water heaters face the equator and are angled according to latitude to maximize solar gain. IV. Solar Energy Photovoltaic: Converts solar radiation directly into electricity Residential building with solar panels on one side (Bern, Switzerland). 7

8 IV. Solar Energy Advantages of solar energy: Inexhaustible fuel source No pollution Often an excellent supplement to other renewable sources Versatile--is used for powering items as diverse as solar cars and satellites Disadvantages of solar energy: Very diffuse source means low energy production--large numbers of solar panels (and thus large land areas) are required to produce useful amounts of heat or electricity Only areas of the world with lots of sunlight are suitable for solar power generation VI. The Transition Some Barriers to Acceptance: Lack of government policy support Lack of information dissemination and consumer awareness. Higher capital cost of renewable energy technologies compared with conventional energy technologies. Difficulty overcoming established energy systems Inadequate workforce skills and training, which includes lack of adequate scientific, technical, and manufacturing skills required for renewable energy production Lack of adequate codes, standards, utility interconnection, and netmetering guidelines. Lack of stakeholder/community participation and co-operation in energy choices and renewable energy projects. 8

9 VI. The Transition Now for the good news: Renewable energy resources provide just over six percent of the total energy used in the U.S. today. California is a leading state and 31 percent of California's electricity comes from renewable sources. Most of this renewable electricity comes from hydropower, but 12 percent comes from "new" renewables which include wind and geothermal energy. Many of the new technologies that harness renewables including wind, solar, geothermal, and biofuels are, or soon will be, economically competitive with the fossil fuels that meet 85 percent of U.S. energy needs. The UNEP report says investment capital flowing into renewable energy climbed from $80 billion in 2005 to a record $100 billion in The increased levels of private investment and the fact that much of the capital is coming from more conventional financial actors suggest that sustainable energy options are now becoming mainstream 9